The present study evaluated in vitro and in vivo the effects of quercetin (QC), a major ingredient in various flavonoids, on peripheral nerve regeneration.
In the in vitro study, we found that QC at concentrations of 0.1, 1, and 10 µg/mL could significantly promote the survival and outgrowth of cultured Schwann cells as compared with the controls treated with culture medium only. In the in vivo study, we evaluated peripheral nerve regeneration across a 15-mm gap in the sciatic nerve of the rat, using a silicone rubber nerve chamber filled with the QC solution. In the control group, the chambers were filled with normal saline only.
At the end of 8 weeks, morphometric data revealed that all 3 QC groups significantly increased the count and density of myelinated axons as compared with the controls. Electrophysiological measurements showed that the QC-treated group at 1 µg/mL had a significantly larger area of evoked muscle action potential (MAP) compared with the controls. In addition, the amplitude of the MAP in the QC-treated groups at 0.1 and 1 µg/mL was significantly larger than that in the controls.
All of these results indicate that QC treatment has nerve growth-promoting effects which may lead to a promising herbal medicine for the recovery of regenerating peripheral nerves.